Knob-insulator.



PQ GRACE.

KNOB INSULATOR.

APPLIoAToN FILED JUNE 12,1907.

1 mem@ Feb, m10.

i sessel.

UNITED STATES PATENT QFFlCE.

SERGUS .'P. GRACE, PITTSBURG, PENNSYLVANIA, ASSIGNOR TG 'W'ESTEBN ELECTRIC COMPANY, F CHICAGO, ILLINOIS, A CRPORATION @F ILLINOLVS.

KNOB-NSULTOR.

Specification of Letters Patent.

Patented Feb. 8, 1916.

Application led June 12, 1907. Serial No. 378,625.

To all 'whom it may concer/n.'

Be it known that I, SERGIUS l. GRACE, citizen of the United States, residing at iittsl'iurg7 in the county of Allegheny and State of Pennsylvania, have invented a certain new and useful Improvement in Knoblnsulators, of which the following is a full, clear, concise, and exact description.

My invention relates to a knob insulator for supporting e twisted pair of wires, and its object is to provide an insulator that will support the wires without injuring them.

My invention consists of an insulator knob having two parallel grooves about its periphery, each groove being adapted to receive one wire of e pair, the wires being thus held in separate relation to each other 'around the knob. In its preferred form,

the insulator comprises a cylindricalknob having a largegroove around its circuin terence, and having two smaller grooves formed in `the bottoni of the larger groove, each of said smaller grooves being adapted to receive a single wire.

Asis wellknown, it is common to twist together two wires Yforming electrical conductors, such twisted wires each being coated or covered with insulating material. It has been found that. it such a twisted pair be .'ugiuiorted by being wrapped about the insulutoi in the usuel nianner, there is a great liability of the insulation being 'cut intol und the wires consequently short-circuited at the point they` cross each other about the insuintino knob. rthis is obviously due to the it'iict that one ot' seid wires is held against the insulating knob and supports the other,-

the stress or weight of the depending ends thus causing the wires to cut intol each other.

`My invention provides an insulating knob which lwill hold the two wires in separate relation, at their point of support and prevent i eir crossing each other. My invention aise provides better support for the wires, since the double groove insulator gives a greeter bearing surfaceffor each wire ot the pair.

My invention 'will be more readily understood by reference to the accompanying drawing in whichli ignre 1 is aneno elevation of the knob; Fig. is e central longitudinal section thereof; Fig. 3 is a. side view of the knob with a pair of wires wrapped thereebout, and showing the saine before the tie-wire is applied; Fig. 4 is e similar view showing the first position ot the tie-wire; Fig. 5 1s a front side View of the complete tie; and Fig. 6 is a rear side view oi? the complete tie.

Like parts are designated by similar' characters of reference throughout the several views.

The knob 1 is formed of insulating niaterial and is preferably of cylindrical forni having an o ening 2 through its longitudinal center, y means oit' which it may be secured upon the cross-arm, the side of a house or other suitable support-iii the usuel manner. The outer circumference of said knob is provided with a large groove 3, the bottom of whichl is formed into two smaller grooves l, 4, each ot said latter grooves being of a size adapted to receive a single wire of the twisted pair. Said grooves 4, 4, are preferably separated by a ridgesliaped rib 5. ln wrapping the twisted wires about the knob, `said wires nre more readily separated by means of the rib or ridge 5, sind there is little likelihood of their crossing one over the other.

The method ot tying the pair of wires to the insulating support is shown in Figs. 3, 4:, .5 and t3, in which a twisted. pair 6 is wrapped about the knob l in the groove 3. The portions of the pair surrounding the knob are separated by the ridge 5 end the wires lie in the groove e in parallel relation to each other as shown inost clearly in Fig. 6. While in this position a short tie-wire 7 is placed around the knob end wire er tending over the pair et the right of Fig. e, and under the seine at the left oit said figure. The ends ot the wires '.7 are then wrapped about the pair es shown in Fig. 5 and Fig. 6 to forni the compiete tie. lt is 'thus ap parent that the wires of the twisted pair are securely held in seperate relation around the circumference oit' the knob and that it is impossible -for there to cross one another, and hence any short-oircuiting due to the. strain of the span et wires against the knob is revented.

s before stated, l preferably forni the grooves et, 4 in the bottom of the larger groove 3.. By this construction the top portion `of the groove 3 is adapted to receive the tie wire 7 `end prevents any possibility of the wires slipping off ot the insulator knob. l

The knob insulator of my invention is designed more particularly for use with the usual twisted drop or house wires which extend from the cross arms of poles which support the telephone line Wires to the house in which the telephone substation is located. in inodern practice, it is common to form such drop wires of 'a twisted pair of rubbercovered wires. The insulating knob of my invention is particularly adapted to form asupport for the ends of the drop wires at the points of their connection to the line wires and the house to which said drop wiresV extend, the knob being of such construction, as hereinbefore stated, that the twisted pair may be readily secured to the same without endangering the insulating covering of the wires.

claim i l. An insuiator comprising a knob of circular cross-section provided with a groove in its circumference and having an annular rib extending completely around the knob at the bottom of said roove, said rib being of a height less than t e depth of said groove and dividing the bottom ot' the groove into two smaller grooves.

2. The combination with a twisted pair of conducting wires, of an insulator support therefor consisting of a cylindrical knob provided with an annular main groove and iaving an annular rib with a sharp-pointed vertex located at the bottom of said groove,rsaid rib being of a height less than the depth of said groove und dividing the bottom of the main roove into two smaller grooves, and a tie-wire for tying said pair of wires to said knob; said rib serving to separate said wires, ywhen said pair of wires is wrapped about said knob, and to leave a space 1n the main groove above said rib for receiving said tie-wire.

En witness whereof, i, have hereunto subscribed my naine this 7th day of J une gli. D.,

SERGIUS P. GRACE. 'Witnessesz v J. F. MCKENNA, J. MGKENNA. 

